The news broke recently that more and more websites make money by mining cryptocurrencies on their visitors’ computers. A person browses a site, unaware that their CPU is loaded more than normally, working on a task they didn’t put. The device slows down, making its owner less happy and productive.

On the other hand, this type of mining can let websites earn money without selling ads.
The Pirate Bay, that had been recently caught mining cryptocurrencies on the visitors’ computers, shows the type of ads that annoy people a lot. A part of its audience might be ready and willing to lend some of their computer power in order to support the website and get rid of the ads.

One of the tools that now gain popularity for enabling mining on a website is Coinhive. They provide a JavaScript miner for the cryptocurrency called Monero. We at AdGuard taught our desktop apps to detect the Coinhive miner on websites and ask users whether they would allow it to use their computer. We believe that it is not right to simply block it, but warning the user and asking for his or her consent is necessary.

We work at detecting other mining tools as well. So if you notice any websites that use your device for mining without warning you and asking for permission, please report us.

And you should not worry too much about this news and expect every web page to abuse your CPU. Only websites with a really large audience can earn somewhat substantial money by mining on users’ devices.